Control for delivery of power to heating elements

ABSTRACT

The invention relates to a control and switching apparatus for electric heating, comprising a micro-processor-based operation control unit (2) provided with control switches, and a regulating circuitry unit (5) associated with said control unit and comprising a plurality of regulating circuits. At least some of the regulating circuits are connectable to electronic sensors (8), whereby the combined effect of measuring messages fiven by said sensors, control data from the operation control unit (2) as well as set values (6) selected by the regulators provides the basis on which the regulating circuits (5) are adapted to control the ON/OFF-switches of electric loads, said switches being triac-switches (9a). One regulating circuit can be modified to operate as a regulating circuit suitable for controlling an electric sauna stove, said circuit being connectable, by means of a selector device, in power transposition with one or several other regulating circuits.

BACKGROUND OF THE INVENTION

In electrically heated houses, the heating control is normally effectedwith thermostats, one in each room.

An object of the invention is to provide a microprocessor-basedapparatus suitable for the roomwise heating control and regulation ofelectrically heated houses in a manner that the heating of each room canbe controlled and regulated in a centralized manner with a singleapparatus.

A further object of the invention is to develop an apparatus whichallows the addition of new functions to the heating control at minorextra costs.

Another object of the invention is to develop an apparatus whosefunctions can be designed variable for taking the requirements ofvarious applications better into consideration.

A still further object of the invention is to provide a controlapparatus that can be placed in the instrument space of an electricitycentre or immediately nearby, the electric heating system of a housethus providing a simple unit.

SUMMARY OF THE INVENTION

For achieving these objects, the invention relates to an electricheating control and switching apparatus, comprising amicroprocessor-based operation control unit, provided with controlswitches, and a regulating circuit unit, associated with said controlunit and comprising a plurality of regulating circuits, each of saidregulating circuits controlling directly the heating elements of a room.

An apparatus of the invention is characterized in that at least some ofthe regulating circuits can be connected to electronic sensors, wherebythe combined effect of measuring messages given by said sensors, controldata from the operation control unit as well as set values selected bythe regulators provides the basis on which the regulating circuits areadapted to control the ON/OFF-switches of electric loads, which areconventional prior known triac-switches. Each regulating circuit thusreceives the necessary control and regulation data from roomwisetemperature sensors, set value selection switches and an operationcontrol processor. This three-way control of regulating circuits makesit possible to achieve the aims and objectives of the invention.

The use of triac-switches at control outputs offers the followingadvantages:

possibility for zero-point connection thus minimization of mainsinterruptions,

improved control precision by virtue of shorter operating cycles,

prolonged service life compared to relays.

In a preferred embodiment of the invention, one of the regulatingcircuits of said regulating circuitry is preselected to be modified bymeans of a connection associated with the apparatus as a regulatingcircuit suitable for controlling an electric sauna stove and theapparatus comprises a selector device for switching said regulatingcircuit in power transposition optionally with one or several otherregulating circuits.

An apparatus of the invention is preferably designed so as to compriseat least 10, preferably approximately 15 regulating circuits, just someof said circuits including their own thermometry, set value selectionand control output while the rest of said regulating circuits includetheir own thermometry and control output, but their set value selectionsare common with the first-mentioned group of regulating circuits. Inpractical design, this is preferably embodied in a manner that theoperating panel only includes temperature set value rotating switchesfor some of the regulating circuits and that a regulating circuitscross-switching means, included in the apparatus, the rest of saidregulating circuits are freely selectable to follow the set value of adesired rotating switch.

The apparatus can be readily designed so that some of the regulatingcircuits can be used for lighting control. In that case, at least one ofthe electronic sensors used will be a dimmer switch, whereby theregulating circuit associated therewith is connectable to lightingcontrol.

Other embodiments, details and features of the invention will be furtherdescribed in the following specification with reference made to theaccompanying drawings and enclosures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an operating block diagram for a control apparatus and

FIG. 2 is an elevation of a mechanical embodiment of said controlapparatus.

FIGS. 3-6 show an operating panel and functions of the switches includedtherein.

FIGS. 7-11 illustrates applicationwise programming of the apparatus bymeans of peak strips in the front panel.

FIG. 12 illustrates switching of temperature sensors and actuatorinterface as well as contact data interface in the line terminal of thelow-voltage section of this apparatus.

FIG. 13 illustrates the connection of heaters to the power supplyterminals of this apparatus, the triac-switches controlled by regulatingcircuits being fitted between the pairwise arranged input and outputconnections of said terminals.

DETAILED DESCRIPTION OF THE INVENTION

In the block diagram shown in FIG. 1, all blocks included in a centralunit 1 are fitted in a single assembly that can be fitted in standardelectricty centres or encapsulated in its own housing. Reference numeral2 designates a microprocessor-based operation control unit, based e.g.on the use of a single-capsule processor Motorola MC146805 E2. The useof a single-capsule processor provides for a simple embodiment of thedigital section and a small number of components. Digital electronicscan be mounted on a single card which also includes control switches anda fault-indicator light, which are part of the operating panel FIG. 3.The control unit 2 is provided with a parameter memory unit 3 that canbe used to modify the properties of control unit 2 as required byvarious applications.

The operation control unit is associated via a contact interface 4 withoperating panel 300 control switches (see FIG. 2 and FIG. 3), "heatingON/OFF" switch 309, "temperature drop -5/0/-2° C." switch 310,regulation control switch ON/OFF" switch 311 and electric sauna stovecontrol switch (S1, FIG. 11.

The control unit 2 is connected to a regulating circuit unit 5,including e.g. 15 regulating circuits for room temperatures. Eachregulating circuit controls a triac-switch 9a fitted in a control outputunit 9, electric power being supplied through said triac-switch directlyto heating elements. Thus, the control output unit 9 is provided with 15inputs and 15 outputs, said triac-switches 9a being fitted therebetween.These inputs and outputs are shown in FIG. 1 and FIG. 13 as mainsvoltage line terminals L1, L2 and L3.

Room temperature sensors 8 can be linked via a measuring interface 7(see FIG. 12) to the regulating circuits of regulating circuit unit 5.Set value selections for regulating circuits can be made by means ofrotating switches included in unit 6 and shown on the operating panel ofFIG. 3 with references 1-8. Thus, there are fewer set value switchesthan regulating circuits. For this reason, some of the regulatingcircuits are adapted by means of a special regulating circuitscross-switching means (FIG. 7) to follow as a slave circuit the setvalue of a desired, freely selectable rotating switch.

The operation control unit 2 is associated with an actuator interface10, whereby said operation control unit 2 can be in serial datatransmission contact with an external actuator 11. By way of interface10, said control device 2 can supply data of measuring results, setvalues, states of controls and possible malfunctions e.g. at 4 secintervals. On the other hand, operation of the entire apparatus andoperation of the regulating circuits in regulating circuitry unit 5 canbe remote-controlled by way of control device 2 by using commands issuedby actuator 11 through interface 10. By virtue of a ready interface 10,the expansion of functions of this apparatus is possible withoutmodifications to the control and switching apparatus. The question canbe about an intelligent actuator, including a timer and capability ofproducing time programs. The actuator can, by way of interface 10,positively or forcibly control the operation of a control and switchingapparatus and monitor and control temperatures in a house.

For example, thermistor-type of sensors can be selected for temperaturesensors 8. An advantage offered by thermistors is high sensitivity whichis one of the factors leading to simple amplifier electronics.

In designing the regulating circuits of regulating circuitry unit 5 itis readily possible to consider eventual use for other purposes as well,e.g. for controlling outdoor lights on the basis of a lighting sensor ordusk switch.

A control and switching apparatus of the invention must include a backupfunction that can be switched on to control heating instead of aprocessor control, e.g. at the time of maintenance or malfunction.Therefore, the central unit is provided with a backup thermostat 13 thatcan be switched on operation by means of a regulation control switchassociated with a contact interface 4 (see also FIGS. 3-6). In theOFF-position of a regulation control switch, said backup thermostat 13controls all triac-switches 9a that are under the control of controloutput unit 9. The fixed set value of backup thermostat 13 is e.g. 21°C. and to said thermostat is connected a temperature sensor 8 for someroom measuring.

The operation of operation control unit 2 proceeds as control cycles offixed duration (e.g. 4 sec). Functions included in a control cycle aree.g. a read-out program for the control switches associated with contactinterface 4, a read-out program for the set values issued by therotating switches included in a set value selection unit 6, a measuringprogram for the temperature data issued by temperature sensors 8, atemperature regulation program on the basis of such data as well as aserial communications activation program (transmission). The regulationfunction file further includes a monitoring program to be run once everycontrol cycle. The control apparatus runs tests on itself and checks onthe intelligence of the operation. If a fault is found in the operation,it is reported to a user by switching on a fault-indicator light 12.

In some cases it may be necessary to control a greater power thanpossible with triac-switches (e.g. over 1400 W). In this case, use ismade of "a selection 1" peak strip shown 800 in FIG. 2 and FIG. 8. Byfitting the peak strip at a desired regulating circuit (1-15) ashort-circuit bit, a relay operation is provided on the correspondingregulating circuit.

By means of "a selection 2" peak strip 1000 (FIG. 2 and FIG. 10), aregulating circuit "1" can be modified for sauna stove control byfitting a short-circuit bit between the peaks associated with regulatingcircuit 1.

The "selection 2" peak strip 1000 can be used to connect one or severalregulating circuits 2-15 to power transposition with regulating circuit1 modified for sauna control by fitting the short-circuit bits betweenthe peaks associated with regulating circuits chosen for powertransposition. FIG. 11 illustrates a circuit diagram for connecting anelectric sauna stove with the control of a control and switchingapparatus of the invention. Thus, the central unit of the apparatus isprovided with a separate sauna sensor and the control is effected by wayof a contactor.

The power and connecting electronics of central unit 1 of this controland switching apparatus for temperature measurements, contact inputs, aseparate actuator and control outputs is mounted on a second card of theapparatus, said card including also a power source (e.g. +5 V) requiredby electronics. The triac-switches serving as power switches are mountedon a cooling panel (FIG. 1, part 4). The card for control circuits andthe card for power circuits are positioned in a manner that theirconnecting terminals will be positioned on opposite sides of saidcooling panel fitted with cooling ribs, as shown in FIG. 2.

FIGS. 3 through 6 show the operating panel 300 and functions of theswitches 301-311 and indicator light 312 included therein.

As best viewed in FIG. 3, switch 309 is a heating control ON/OFF switch.Switch 310 is a temperature drop selection switch, for selecting atemperature drop of -5, 0 or -2° C. (degrees Celsius). Switch 311 is aregulation control ON/OFF switch. Lamp 312 is a fault detector light.Switches 301-308 are rotating switches which provide roomwise regulatingcircuits with a desired set values of 14° to 25° C.

As shown in the table of FIG. 4, the eight rotating switches 301-308correspond (match) to eight of the aforementioned fifteen regulatingcircuits in the regulating circuit unit 5 of FIG. 1. These regulatingcircuits are numbered 1, 2, 3, 6, 7, 8, 11 and 12 in the table.

With respect to the heating control ON/OFF switch 309, in theON-position a micro-computer controls the roomwise regulating circuits(included in unit 5 of FIG. 1) according to the set temperature values(as provided by the rotating switches 301-308). In the OFF-position ofthe heating control switch 309, the micro-computer is not operating, noris the heating on. The heating control switch has no effect on theoperation of the sauna control.

As shown in FIG. 5, heating can also be switched off by means of theclosing time contact 502 of a tariff timer or one week program controlas follows:

With respect to the temperature drop switch 310, the switch is tristable(three position), and achieves a temperature drop on all regulatingcircuits (included in the unit 5 of FIG. 1) simultaneously, either -2°or -5° C. down from the set values (of switches 301-308). The "0"position is for no temperature drop. However, the temperature is notpermitted to drop below 13° C., in any case. For instance, if the setvalue (of one of the switches 301-308) is 15° C., and the temperaturedrop set switch 310 is set to -5° C., the temperature is not permittedto drop to 10° C., but is limited to 13° C.

As shown in FIG. 6, the temperature drop can also be initiated by meansof an external contact control 600. The control 600 includes a three-wayswitch 602 to initiate the aforementioned -2, 0 and -5° C. temperaturedrops.

With respect to the regulation control ON/OFF switch 311, in the ONposition, the microcomputer of the control apparatus is in normaloperation. In the OFF position, heating is controlled by the backupthermostat of the apparatus, whose fixed set value is 21° C. Connectedto the thermostat is a temperature sensor of room measuring 2. In thebackup heating operation mode, all control outputs are controlledsimultaneously. The regulation control switch 311 is useful insituations where the ambient temperature is too low for microcomputeroperation and in case of malfunctions.

With respect to the fault indicator light 312, the controller runs testson itself and checks on operation intelligence. If a fault is found inoperation, it is reported to the user by switching on the faultindicator light 312. The fault indicator light 312 switches on if:

any of the measuring inputs is short circuited; any of the measuringinputs are open (e.g., sensor cable broken; any of the rotating switchesfor temperature set values (301-308) has stopped in an intermediateposition; or the regulating circuits cross-switching means is off orincorrectly connected.

In the case of such a fault, a corresponding control output isautomatically switched off.

FIGS. 7-11 illustrate application-wise programming of the apparatus bymeans of peak strips in the front panel.

FIG. 7 shows the cross switching means 700, and the connections to thefifteen regulating circuits (numbered 1-15) included in the regulator 5of FIG. 1. As noted hereinbefore with respect to the table of FIG. 4,eight regulating circuits (nos. 1, 2, 3, 6, 7, 8, 11 and 12) correspondto the eight rotating switches 301-308 on the operating panel. Theremaining seven regulating circuits (nos. 4, 5, 9, 10, 13, 14 and 15)are freely selectable (slave) regulating circuits.

In the cross-switching means, the regulating circuits are freelyprogrammable as to which temperature set value switch 301-308 on theoperating panel control which slave circuit (nos. 4, 5, 9, 10, 13, 14and 15). This free programmability is illustrated by the dashed linesindicating jumpers between the regulating circuits.

If one of the freely selectable (slave) regulating circuits remainsunused, it must be "chained" under a rotating switch (301-308) in thecross-switching means 700. (This is illustrated, for instance, by thedashed line connections between circuit nos. 4, 5 and 9.) Otherwise, thesituation would be interpreted as a fault, and the fault indicator light312 would come on, as previously discussed.

FIGS. 8 and 9 illustrate the relay operation of the regulating circuits(nos. 1-15). By way of example (selection 1), regulating circuit no. 14is discussed. Relay operation on regulating circuit no. 14 is indicatedby a dashed line 802. The alternative relay operation of control outputsis programmed with a short-circuit bit by placing it on the regulatingcircuit in question. In other words, in relay operation:

Short-circuit "n"=ON, regulating circuit no. "n", (where "n" is from 1to 15)

In use, if the power of room space heaters exceeds 1400 W (Watts), acontractor control is used. Thus the regulating in question isprogrammed in relay operation and the contactor is circuited as shown inFIG. 9, e.g., for regulator circuit no. 14.

FIGS. 10 and 11 illustrate sauna control and power transposition forregulating circuits nos. 1-15. By way of example (selection 2),regulating circuit no. 1 is discussed, as indicated by the dashed line1002. For regulating circuit no. 1, the peak strip selection 2 can beused to define the control of an electric sauna stove (heater). Saunacontrol and power transportation are effected by short circuiting theappropriate regulating circuit as follows:

Short circuit "1"=ON, reguating circuit "1"; Sauna control;

Short circuit "n"=ON, rregulating circuit "n"; power transportation(where "n" is from 2-15).

The electric sauna is connected to the Thermoset (Termoset) asillustrated in FIG. 11, which shows a sauna stove control switch,labeled S1, and a sauna stove control contactor, labeled K1. The saunastove switches off automatically, and four hours later will restart withthe switch S1. As the sauna stove switches on, the regulating circuitschosen for power transportation switch off.

FIG. 12 illustrates the circuitry for temperature sensors, for instancea temperature sensor 1201 in a first room (Room 1) and a temperaturesensor 1202 in a second room (Room 2); in other words, the witching oftemperature sensors and the actuator interface, as well as the contactdata interface in the line terminal of the low-voltage section of thisapparatus. It should be noted that in the unused measuring spaces (e.g.,rooms 5-15), it is necessary that a resistance "R" (R=47 kilo-ohms) beswitched on (installed on the terminal strip J6) unless the sensor is on(hooked up). Otherwise, the processor would interpret the lack of asensor as a fault (e.g., open circuit), with the aforementionedconsequences.

FIG. 13 illustrates the circuitry for controller supply and heaters; inother words, the connection of heaters to the power supply terminals ofthis apparatus, the triac-switches controlled by the regulating circuitsbeing fitted between the pairwise arranged input and output connectionsof said terminals. Regulating circuits nos. 1-15 are illustrated. Itshould be noted that, when switching on, the controller supply andsupply for the regulating circuits nos. 1-5 must be in the same phase.

What is claimed is:
 1. An apparatus for controlling the delivery of power from a power source to a plurality of electric heating elements, said apparatus comprising:a plurality of electronic switches for delivery of power from a power source to a plurality of heating elements; a plurality of temperature sensors associated with said heating elements; control means, responsive to said temperature sensors, for activating said electronic switches to provide a desired level of heat output; and selection means coupled to said electronic switches for selectively delivering both the output from each of said switches to a different heating element to deliver relatively low power to heating element, and the output from at least two of said electronic switches to one of said heating elements to deliver relatively high power to the one heating element.
 2. An apparatus as set forth in claim 1 wherein each switch comprises a triac, the control means includes a plurality of regulating circuit means for activating said switches at phase angles corresponding to the desired levels of heat output, and the selection means includes means for switching one of the regulator circuit means in power transportation with at least one other of the regulator circuit means to deliver the power from the associated electronic switches to the one heating element.
 3. An apparatus as set forth in claim 1 wherein said control means includes processor means, responsive to said temperature sensors and to set temperature values programmed into said processor means, for controlling the amounts of power delivered to said heating elements via said electronic switches to attain said set temperatures.
 4. An apparatus as set forth in claim 2 wherein said control means includes processor means, responsive to said temperature sensors and to set temperature values programmed into said processor means, for controlling the amounts of power delivered to said heating elements via said electronic switches to attain said set temperatures.
 5. An apparatus for controlling the delivery of power from a power source to a multiplicity of electric heating elements, said apparatus comprising:a multiplicity of electric heating elements; a multiplicity of electronic switches, one associated with each of said heating elements and interposed between a power source and the associated heating element; thermometry means, associated with said heating elements, for measuring the temperatures of objects heated by each of said heating elements; means for setting desired temperatures for said objects; a multiplicity of regulator means, responsive to the thermometry means and the setting means, for controlling the electronic switches in accordance with the set temperatures to delivery power to the associated heating elements; and manually operable temperature drop switch means for effectively lowering the set temperatures by a predetermined amount for a plurality of said regulator means simultaneously; and wherein said multiplicity of regulator means are also responsive to said temperature drop switch means, for controlling the electronic switches in accordance with the set temperatures to delivery power to the associated heating elements.
 6. An apparatus for controlling the delivery of power from a power source to a plurality of electric heating elements, said apparatus comprising:a plurality of electronic switches for delivering power from a power source to a plurality of heating elements; a plurality of temperature sensors associated with said heating elements; control means, responsive to said temperature sensors, for activating said electronic switches to provide a desired level of heat output; and selection means coupled to said electronic switches for selectively delivering either the output from each of said switches to a different heating element to deliver relatively low power to each heating element, or the output from at least two of said electronic switches to one of said heating elements to deliver relatively high power to the one heating element; and wherein each switch comprises a triac, the control means includes a plurality of regulating circuit means for activating said switches at phase angles corresponding to the desired levels of heat output, and the selection means includes means for switching one of the regulator circuit means in power transportation with at least one other of the regulator circuit means to deliver the power from the associated electronic switches to the one heating element; and the delivery means includes a terminal strip having terminals associated with each of the regulator means and switches, and means for interconnecting the terminals to select which of the regulator circuit means are coupled together to deliver power to said one heating element.
 7. An apparatus for controlling the delivery of power from a power source to a plurality of electric heating elements, said apparatus comprising:a plurality of electronic switches for delivering power from a power source to a plurality of heating elements; a plurality of temperature sensors associated with said heating elements; control means, responsive to said temperature sensors, for activating said electronic switches to provide a desired level of heat output; and selection means coupled to said electronic switches for selectively delivering either the output from each of said switches to a different heating element to deliver relatively low power to each heating element, or the output from at least two of said electronic switches to one of said heating elements to deliver relatively high power to the one heating element; and wherein each switch comprises a triac, the control means includes a plurality of regulating circuit means for activating said switches at phase angles corresponding to the desired levels of heat output, and the selection means includes means for switching one of the regulator circuit means in power transposition with at least one other of the regulator circuit means to deliver the power from the associated electronic switches to the one heating element; and further comprising second selection means, coupled to said plurality of regulating circuit means, for programming a relay operation on a desired regulating circuit.
 8. An apparatus for controlling the delivery of power from a power source to a plurality of electric heating elements, said apparatus comprising:a plurality of electronic switches for delivering power from a power source to a plurality of heating elements; a plurality of temperature sensors associated with said heating elements; control means, responsive to said temperature sensors, for activating said electronic switches to provide a desired level of heat output; and selection means coupled to said electronic switches for selectively delivering either the output from each of said switches to a different heating element to deliver relatively low power to each heating element, or the output from at least two of said electronic switches to one of said heating elements to deliver relatively high power to the one heating element; and wherein said control means includes processor means, responsive to said temperature sensors and to set temperature values programmed into said processor means, for controlling the amounts of power delivered to said heating elements via said electronic switches to attain said set temperatures; and further comprising a plurality of manually operated temperature set switches, and wherein the control means further includes at least ten regulating circuits interposed between said processor means and said electronic switches, each of said regulating circuits being responsive to a first, common control signal produced by said processor means, a non-common, second control signal produced by an associated temperature sensor and a non-common, third control signal produced by an associated temperature set switch, said first, common control signal providing common control of said regulating circuits. 